Ports are broken for draw2d.shape.analog.* after serialize/deserialize to JSON

[rudolphi]

As no class name for the custom MyInputPortLocator/MyOutputPortLocator subclasses is serialized, only dummy "Class.extend" objects are created during deserialization. The probably best solution would be to just serialize the node IDs of these ports, so that the IDs can be put back during deserialization, to maintain connections, etc.